The present invention relates to a heat exchanger which comprises a plurality of tubes layered with fins intervened between them, header pipes disposed on both ends of the tubes, and side plates for holding the tube layer.
A generally known heat exchanger is configured by stacking a plurality of tubes with fins intervened between them, and connecting to communicate respective end portions of the tubes with header pipes disposed on both sides of the tube layer. According to this configuration, a medium for heat exchanging flows to meander a plurality of times between inlet and outlet joints disposed on the header pipes to make heat exchange with the atmospheric air while flowing.
This type of heat exchanger is improved its structural strength by disposing side plates for holding the tube layer. Specifically, the side plates are connected with the outermost fins of the tube layer, and their end portions are supported by the respective header pipes.
Generally, each member of the tubes, the header pipes, the fins and the side plates is formed of a metallic material clad with a brazing material by shaping into a predetermined form. And the formed members are assembled by means of a jig and the like, the assembly is sent into a furnace and heated so to be brazed into one body. Especially, the side plates are inserted at both end portions into and brazed to the side plate insertion holes formed at the essential portions of the header pipes.
The aforesaid side plate insertion holes are formed to have such a size that the end portions of the side plates are inserted without rattling. Thus, when the end portions of the side plates are inserted into and brazed to the side plate insertion holes, airtightness and watertightness of the header pipes are secured without fail.
Therefore, it is a very troublesome job to insert the end portions of the side plates into the side plate insertion holes, causing lowering of the productivity of the heat exchanger.
Particularly, a taper for increasing an opening area is conventionally formed on the inner periphery of the side plate hole to make it easy to insert the end portion of the side plate. But, such tapering work was very hard because a machine and a tool are obstructed within the side plate holes.
Accordingly, in view of the aforesaid drawbacks, it is an object of the present invention to provide a heat exchanger which can have the side plates assembled with ease.
The invention recited in claim 1 is a heat exchanger comprising a plurality of tubes layered with fins intervened between them, header pipes disposed on the end portions of the tubes, and side plates for holding the tube layer, wherein each of the side plates is connected to a side plate insertion hole formed on the header pipe by inserting its end portion into the side plate insertion hole, and forming a taper on the end portion of the side plate to decrease its thickness toward its leading ends.
Thus, the heat exchanger of the present invention is formed the taper at the end portions of the side plates to decrease the thickness toward the leading ends, so that the end portions of the side plates can be easily inserted into the side plate insertion holes of the header pipes. In other words, when the end portions of the side plates are to be inserted into the side plate insertion holes, they can be guided in position by the tapers even if the positioning is deviated somewhat in the thickness direction.
Therefore, the assembling property of the side plates can be improved, and the productivity of the heat exchanger can also be improved accordingly.
Particularly, the taper for increasing the opening area is conventionally formed on the inner periphery of the side plate insertion hole in order to facilitate the insertion of the end portions of the side plates, but such tapering work is quite difficult because a machine and a tool used are obstructed within the side plate insertion holes. But, the present invention can remedy such a disadvantage because the end portions of the side plates are tapered.
The invention described in claim 2 is the heat exchanger according to claim 1, wherein the end portions of the side plates are tapered toward the leading ends to decrease their width.
Thus, the heat exchanger of the invention is formed the taper at the end portions of the side plates to decrease the width toward the leading ends, so that the end portions of the side plates can be easily inserted into the side plate insertion holes of the header pipes. In other words, when the end portions of the side plates are to be inserted into the side plate insertion holes, they can be guided in position by the tapers even if the positioning is deviated somewhat in the width direction.
Therefore, the assembling property of the side plates can be further improved.
The invention recited in claim 3 is the heat exchanger according to claim 1 or 2, wherein contact portions are formed on the side plate to contact with the outer surface of the header pipe, and the contact portions are brazed with the outer surface of the header pipe.
Thus, the heat exchanger of the invention brazes the contact portions of the side plate to the outer surface of the header pipe, so that the supporting strength of the side plate can be improved, and its structural strength can be improved.
And, when the end portion of the side plate is inserted into the side plate insertion hole, the side plate can be positioned by contacting the contact portions to the outer surface of the header pipe. Therefore, the side plate can be assembled accurately.
The invention recited in claim 4 is the heat exchanger according to claim 3, wherein the header pipe has a round tubular shape, and the contact portions have a curvature to externally fit to the outer surface of the header pipe.
Thus, in the heat exchanger of the invention, the contact portions of the side plate have a curvature to externally fit to the outer surface of the header pipe having a round tubular shape, so that the supporting strength of the side plate can be further improved, and its structural strength can be further improved. In other words, it is effected because the contact and the brazing of the contact portions and the outer surface of the header pipe are made on a 3-D surface having a depth.
And, since the contact portions are externally fitted to the outer surface of the header pipe, they serve as a reinforcing member of the header pipe, and the header pipe can be prevented from being deformed or damaged.
The invention recited in claim 5 is the heat exchanger according to any of claims 1 to 4, wherein a stopper means is formed on the end portions of the side plates to prevent the end portions of the side plates from coming out of the side plate holes.
Thus, since the heat exchanger of the invention has a stopper means to prevent the end portion of the side plate from coming out of the side plate insertion hole, it is possible to prevent the end portion of the side plate from coming out of the side plate insertion hole until the side plate is assembled and brazed. In other words, the side plate can be attached firmly, and the end portion of the side plate can be brazed securely with the side plate insertion hole.
And, after brazing, the supporting strength of the side plate can be increased by the stopper means, and its structural strength can be improved.